Need To Update XML Tag using Groovy

I have below XML where i need to update some Tags value like 'CUSIP', 'FUND'. I am using below code but it is not helping me.

<?xml version="1.0" encoding="UTF-8"?>
<TRANSACTIONS ASOF_DATE="4/2/2014" CREATE_DATE="4/2/2014" RECORDS="1">
    <TRADE>
        <ACCRUAL_DT>4/1/2014</ACCRUAL_DT>
        <COUNTERPARTY_CODE>1627</COUNTERPARTY_CODE>
        <CUSIP>31384WPS3</CUSIP>
        <DESC_INSTMT>CREDIT INDUSTRIEL ET COMMERCIAL (N</DESC_INSTMT>
        <DESK>a</DESK>
        <DESK_TYPE>GEN</DESK_TYPE>
        <DTM_2A7>7</DTM_2A7>
        <EXECUTION_TIME>4/1/2014 10:03:06.000</EXECUTION_TIME>
        <EXEC_TIME_SOURCE>A</EXEC_TIME_SOURCE>
        <FUND>VIMVP-FI</FUND>
        <INT_AT_MATURITY>536.6666666667</INT_AT_MATURITY>
        <INVNUM>-911223</INVNUM>
        <ISIN>US22536GL746</ISIN>
        <MATURITY>4/8/2014</MATURITY>
        <MULTI_FUND_ID>811610</MULTI_FUND_ID>
        <PORTFOLIOS_PORTFOLIO_NAME>AMMF</PORTFOLIOS_PORTFOLIO_NAME>
    </TRADE>

I am using below code for doing the same-

def xmlFile = "D:\\Invesco\\Alladin\\Test Data Files\\Input\\Transaction_FI.xml"
def xml = new XmlParser(false, false).parse(xmlFile)

xml.'**'.'Trade'.each{

it.@FUND = 'CASH'
it.@INVNUM = '-675'
it.@CUSIP = '3B56GTUNN'

}